Prescription opioid (PO) use, misuse, disorders, and overdose have dramatically increased. Much of this increase is attributed to providers prescribing POs for chronic pain. Compared to HIV- patients, HIV+ patients are particularly at risk because they suffer disproportionately from chronic pain, have greater PO use and higher PO dose, and often have substance use and mental health disorders that increase the risk for PO misuse. Despite high PO use and risk among HIV+ patients, little is known about the relationship between PO use and HIV outcomes. It is possible that some types of PO use (PO use conditions) are associated with poor HIV outcomes, similar to illicit drug use. It is also possible that some PO use conditions are not, for example, PO use without misuse could improve patients' pain, physical function, and retention in HIV care. Very few studies have examined PO use and HIV outcomes, and further, it is unknown how patients' psychosocial functioning, pain/disability, and biomedical factors, as well as provider factors (e.g., opioid prescribing practices) influence the relationships between PO use and HIV outcomes. A lack of evidence exists to guide clinical practice or to develop guidelines or effective interventions. Our overarching goal is to advance the evidence base necessary to guide clinical management of HIV+ patients with chronic pain. Among HIV+ patients with chronic pain (low back pain, osteoarthritis, or neuropathy) receiving care in a large urban medical center, we will examine PO use using three distinct constructs: 1) an ordinal PO use condition based on a pain management framework; 2) continuous PO use conditions of PO dose, misuse, and addiction; and 3) typologies of PO use which we will identify using latent class analysis of PO use characteristics. The specific aims are: 1) to characterize PO use in a cohort of HIV+ patients with chronic pain; 2) to examine the association between PO use conditions and HIV outcomes; and 3) to examine the roles of patient and provider factors in the relationship between PO use conditions and HIV outcomes using structural equation modeling. We hypothesize that: a) a higher value on the ordinal PO use scale will be associated with poor HIV outcomes; b) higher values in the continuous PO use conditions (PO dose, opioid misuse, and addiction) will be associated with poor HIV outcomes; c) distinct typologies of PO use will differ in their association with HIV outcomes; and d) patient and provider factors influence PO use conditions, HIV outcomes, and the relationship between PO use conditions and HIV outcomes. Using a longitudinal cohort design with 12-month follow-up, we will conduct interviews, physical function assessments, urine toxicology tests, HIV viral load (VL) tests, and extract medical record data among 250 HIV+ patients with chronic pain. The primary HIV outcome is VL; secondary outcomes are CD4 count, ART utilization and adherence, and retention in care. Study findings will substantially advance this nascent and critical area of research, provide much needed evidence to guide clinical practice, and identify targets for interventions to improve outcomes in HIV+ patients with chronic pain.